Tcp Status Transitions - Omron CJ1W-EIP21 - 10-2010 Operation Manual

The TCP socket status can be confirmed using the socket status data returned for the FINS command
SOCKET STATUS READ (27 64).
SYN
RECEIVED
CLOSE
snd FIN
FIN
WAIT-1
rcv ACK of FIN
FIN WAIT-2
rcv FIN
snd ACK
Status
CLOSED Connection closed.
LISTEN Waiting for connection.
SYN SENT SYN sent in active status.
SYN RECEIVED SYN received and sent.
ESTABLISHED Already established.
CLOSE WAIT FIN received and waiting for completion.
FIN WAIT 1 Completed and FIN sent.
CLOSING Completed and exchanged FIN. Awaiting ACK.
LAST ACK FIN sent and completed. Awaiting ACK.
FIN WAIT 2 Completed and ACK received. Awaiting FIN.
TIME WAIT After closing, pauses twice the maximum segment life (2MSL).
Appendix C

TCP Status Transitions

CLOSED
Passive OPEN
LISTEN
rcv SYN
snd SYN, ACK
rcv SYN
snd ACK
rcv ACK of SYN
ESTABLISHED
CLOSE
snd FIN
rcv FIN
snd ACK
CLOSING
rcv ACK of FIN
TIME WAIT
Meaning
ACTIVE OPEN
snd SYN
CLOSE
CLOSE
SEND
snd SYN
SYN
SENT
rcv SYN, ACK
snd ACK
rcv FIN
snd ACK
CLOSED
WAIT
CLOSE
snd FIN
LAST-ACK
rcv ACK of FIN
Timeout=2MSL
CLOSED
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